Role of Fe (x=0-0.15) Substitution on Structural, Magnetic, and Transport Properties of the La0.7Sr0.3FexMn1-xO3 System

This paper investigates the effect of Fe substitution on the structural, magnetic and transport properties of the La0.7Sr0.3MnxFe1-xO3 (LSMO) system where x ranged between 0 and 0.15. Samples were prepared using a non-aqueous sol-gel synthesis method. Structural and chemical analysis confirmed the Fe3+ substitution at Mn3+ sites without any impurity phase resulted in a small change in structural parameters of the LSMO. The change in magnetic behavior and Curie temperature of the Fe-doped LSMO is explained through competitive exchange interactions developed in the system. The temperature-dependent resistivity demonstrated that the resistivity of the samples increased with Fe concentration due to different conduction mechanisms related to the ferromagnetic-metallic and paramagnetic-insulating regions. The magneto-transport measurement showed significant improvement in the magnetoresistance due to Fe doping at Mn site, which was attributed to enhancement of the spin-glass phase in Fe doped LSMO system. The reduction in magnetoresistance for higher Fe concentration is explained with the help of percolation threshold mechanism

Use of brick waste for mortar-substrate optimisation of mortar-masonry systems

This paper investigates the effect of brick dust on the water-releasing properties and dewatering of hydrated lime mortars. Dewatering in masonry occurs when freshly mixed mortar is applied to a dry substrate (e.g. fired bricks, stone) and can influence the physical and mechanical properties of the mortar and the mortar-masonry bond. Controlling these properties provides an important opportunity to optimise performance. This study evaluates the water transport kinetics of hydrated lime-brick dust mortars. The study demonstrates that the particle size distribution of the brick dust can effectively control transfer sorptivity and dewatering time. The measured dewatering times correlated to theoretically calculated values demonstrating the ability to accurately predict the dewatering characteristics of a mortar from a knowledge of the mix design. The use of waste brick dust in hydrated lime mortars provides an environmentally friendly alternative to waste disposal by routes such as landfill

Efficiency enhancement in dye sensitized solar cells through step wise cosensitization of TiO2 electrode with N719 and metal free dye

656-664We have used a step-wise cosensitization process to improve the power conversion efficiency (PCE) of dye sensitized solar cells employing N719 and metal free dye TA-St-CA. The DSSC sensitized with N719/TA-St-CA shows a PCE of 8.27% which is higher than for the DSSCs sensitized with either N719 (5.78 %) or TA-St-CA (4.45%). The improved PCE is attributed to the enhanced overall dye loading as well the reduced dye aggregation that has resulted from the usage of dyes with different anchoring units. The enhancement in the PCE has also been attributed to increase in both short circuit photocurrent and open circuit voltage. This was due to the reduced dark current and suppression of back recombination of injected electrons in the conduction band of TiO2 photoanode with the Iions in the electrolyte

Interfacial bond strength and failure modes of traditional and modern repair materials for historic fibrous plaster

Many culturally important historic buildings contain fibrous plaster ceilings. The collapse at London’s Apollo Theatre in 2013, which injured 88 people, highlighted the importance of inspecting and restoring ceilings effectively. This study focuses on traditional and modern materials which are applied to the topsides of existing historic fibrous plaster ceiling elements during repair and maintenance. Fibrous plaster ceilings are commonly suspended from primary or secondary structural roof members using fibrous plaster wadding ties or ‘wads’. The application of additional repair material requires the formation of an interface, defining the strength of the repair. Properties of this interface were evaluated through a novel methodology employing pull-off tests’ of approximately 200 specimens consisting of Alpha plaster, Beta plaster, Jesmonite and Aramid gel. Notably, the effect of fibrous reinforcement, and compatibility with historic and degraded material was also investigated. This study has enabled quantification of interfacial properties and evaluated cohesive and adhesive failure modes. Importantly, the extent of redundancy within historic plaster ceiling practice has been demonstrated, with pull-off occurring from 0.5 kN to 2 kN loading, and the ductile behaviour of repair materials evaluated. Results highlight the importance of surface condition, with clean surfaces exhibiting double the tensile loading capacity compared to soiled (dirty) surfaces representative of those encountered on-site. The significance of this study lies in the quantification of repair material performances and consideration of variations in performance, methodology and in-situ environmental factors. Impact stems from the ability of practitioners to make informed decisions relating to adhesion performance when carrying out repairs. A key outcome is more effective preservation of historic elements in heritage buildings, higher levels of safety and serviceability.</p

Photocatalytic lime render for indoor and outdoor air quality improvement

This article reports a novel photocatalytic lime render for indoor and outdoor air quality improvement that is composed of a lime binder and doped TiO2 (KRONOClean 7000®) nanoparticles. These nanoparticles were distributed throughout the bulk of the finishing render, instead of as a thin coating, thus ensuring the durability of the photocatalytic properties upon superficial damage. The physical properties of these renders were not affected by the addition of nanoparticles except in the case of surface area, which increased significantly. In terms of their photocatalytic activity, these novel lime renders were shown to degrade up to 12% NOx under UV light and up to 11% formaldehyde under visible light

Photocatalytic Lime Render for Indoor and Outdoor Air Quality Improvement

This article reports a novel photocatalytic lime render for indoor and outdoor air quality improvement that is composed of a lime binder and doped TiO2 (KRONOClean 7000®) nanoparticles. These nanoparticles were distributed throughout the bulk of the finishing render, instead of as a thin coating, thus ensuring the durability of the photocatalytic properties upon superficial damage. The physical properties of these renders were not affected by the addition of nanoparticles except in the case of surface area, which increased significantly. In terms of their photocatalytic activity, these novel lime renders were shown to degrade up to 12% NOx under UV light and up to 11% formaldehyde under visible light.This research was funded by the European Union’s Seventh Framework Programme for research, technological development, and demonstration under the Grant Agreement No. 609234 related to the ECO-SEE project: “Eco-innovative, Safe and Energy Efficient wall panels and materials for a healthier indoor environment” This work was partly developed within the scope of the project CICECO–Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. David Maria Tobaldi is overly grateful to Portuguese national funds (OE), through FCT, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of 29 August, changed by Law 57/2017, of 19 July